Multilayer net for draining fluids, particularly for geotechnical use

ABSTRACT

A multilayer net for draining fluids, particularly for geotechnical use, comprising an intermediate layer, constituted by a plurality of intermediate and substantially mutually parallel filaments, and first and second outer layers, which are constituted by first and second outer filaments which are inclined with respect to the intermediate filaments, the intermediate filaments forming an angle other than zero with respect to the main direction of extrusion of the net from an extruder.

BACKGROUND OF THE INVENTION

As is known, U.S. Pat. No. 5,255,998A, assumed included herein by reference, discloses a multilayer net for draining fluids which is generally constituted by a first layer of mutually parallel filaments which is associated with a second layer or intermediate layer of filaments, which also are mutually parallel and in turn are connected to a third layer of filaments, which are mutually parallel and inclined with respect to the filaments of the first layer and the filaments of the intermediate layer.

In such embodiment, the layers are rigidly coupled to each other so as to provide, at the intermediate layer, drainage channels which extend along the direction of extrusion from the extruder.

Because of this, the net, once produced and collected in reels, if it is used for example to provide drainage at roads, must be used in portions which are arranged transversely to the longitudinal extension of the road, since the intermediate layer in practice forms longitudinal channels which accordingly, if the net were used parallel to the axis of the road, would not allow elimination of the drained water.

This method of operation necessarily entails a considerable expenditure of time for laying, with a higher likelihood of defective installation arising from the incorrect side-by-side arrangement of the portions and from the incorrect provision of the joints between the side-by-side layers.

Moreover, there is the risk of having waste of unusable material, and the laying times and costs affect considerably the cost of the completed work.

SUMMARY OF THE INVENTION

The aim of the invention is to eliminate the drawbacks noted above by providing a multilayer net for draining fluids particularly for geotechnical use which can be applied directly along the longitudinal direction of the road yet achieves correct elimination of the drained water.

Within this aim, an object of the invention is to provide a multilayer net which can be installed easily and quickly, allowing to roll the net into a reel or spool easily, thus facilitating transport.

Another object of the present invention is to provide a multilayer net which, thanks to its particular constructive characteristics, is capable of giving the greatest assurances of reliability and safety in use.

Still another object of the present invention is to provide a multilayer net for draining fluids particularly for geotechnical use, which can be obtained easily starting from commonly commercially available elements and materials and is also competitive from a merely economical standpoint.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by a multilayer net for draining fluids, particularly for geotechnical use, according to the invention, comprising an intermediate layer, constituted by a plurality of intermediate and substantially mutually parallel filaments, and first and second outer layers, which are constituted by first and second outer filaments which are inclined with respect to said intermediate filaments, characterized in that said intermediate filaments form an angle other than zero with respect to the main direction of extrusion of said net from the extruder.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become better apparent from the description of a preferred but not exclusive embodiment of a multilayer net for draining fluids, particularly for geotechnical use, illustrated by way of non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a schematic plan view of the net;

FIG. 2 is a sectional view of the net;

FIG. 3 is a view of the net with covering layers applied thereto;

FIG. 4 is a schematic view of the step of the application of a net under a road surface.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the multilayer net for draining fluids particularly for geotechnical use according to the invention, generally designated by the reference numeral 1, comprises an intermediate layer 2, which is provided by a plurality of intermediate filaments 2 a arranged substantially parallel to each other.

A first outer layer 3 and a second outer layer 4 are applied to the intermediate layer 2, are connected on mutually opposite faces and are provided by means of first external filaments 3 a and second external filaments 4 a which, advantageously, are mutually parallel on each layer, but are inclined with respect to the extension of the intermediate filaments.

The intermediate filaments are rigidly coupled to the external filaments so as to provide a monolithic product which is obtained directly during extrusion from the extruder.

The pecularity of the invention consists in that the intermediate filaments 2 a form an angle which is other than 0 with respect to the main direction of extrusion of the net from the extruder, so that when the net 1 is laid parallel to the longitudinal extension of, for example, a road, as shown schematically in FIG. 4, the intermediate filaments 2 a arranged side-by-side form a plurality of small channels, which are inclined with respect to the longitudinal extension of the road, thus easily achieving the removal of the water toward the outside.

The inclination of the intermediate filaments 2 a ranges advantageously from 20 to 90° with respect to the extrusion direction, thus obtaining channels which form an angle with respect to the longitudinal extension of the net, which can vary as a function of the contingent production requirements.

If a drainage under a road surface is being provided, it is advantageous to arrange a plurality of nets side-by-side, arranging them with mutually opposite inclinations of the intermediate filaments so as to obtain an optimum drainage path on the width of the road.

The outer filaments are preferably provided at an angle with respect to each other as well as with respect to the intermediate filaments, so as to provide greater mechanical strength to the net in order to better withstand compression.

Advantageously, first and second outer coating layers 7 and 8 are provided, which are designed to prevent the inflow of material into the net so as to optimize the free channels that remain inside.

The mutual distance of the outer filaments must be calculated so as to prevent the occurrence, under a load, of contact between the outer covering layers, since this would lead to an obstruction of the drainage channels, consequently reducing the efficiency of the multilayer net.

It should be added to the above that the intermediate filaments and the outer filaments in practice form together substantially diamond-shaped meshes with different mutual inclinations, this shape having been found to be optimum.

It has been found experimentally that if the intermediate filaments are provided at right angles with respect to the direction of extrusion it is also advantageous to have the first and second external filaments substantially mutually parallel to each other and perpendicular with respect to the direction of the intermediate filaments; substantially, therefore, the external filaments have a direction which is substantially parallel to the extrusion direction.

From what has been described above it is therefore evident that the invention achieves the proposed aim and objects, and in particular the fact is stressed that a multilayer net is provided in which it is possible to optimize drainage, especially in applications for providing roadbeds and the like, since the net can be laid continuously without having to use the traditional technique of providing portions arranged transversely with respect to the extension of the road.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements.

The disclosures in Italian Patent Application No. MI2006A000498 from which this application claims priority are incorporated herein by reference. 

What is claimed is:
 1. A multilayer net for draining fluids, particularly for geotechnical use, comprising an intermediate layer, constituted by a plurality of intermediate and substantially mutually parallel filaments, and first and second outer layers, which are constituted by first and second outer filaments which are inclined with respect to said intermediate filaments, wherein said intermediate filaments form an angle other than zero with respect to the main direction of extrusion of said net from an extruder.
 2. The multilayer net according to claim 1, wherein said intermediate filaments form an angle from 20 to 90° with respect to the main extrusion direction.
 3. The multilayer net according to claim 1, wherein said first and second external filaments are mutually inclined.
 4. The multilayer net according to claim 1, wherein said first and second external filaments are mutually parallel and said intermediate filaments lie substantially at 90° with respect to the direction of extrusion from the extruder.
 5. The multilayer net according to claim 1, comprising a first external covering layer and a second external covering layer, which are associated respectively with said first and second external filaments.
 6. Use of a multilayer net according to claim 1, wherein said net can be arranged longitudinally with respect to an extension of a road on which transverse drainage is to be provided. 